The perturbation model was proposed by the principal investigator to account for error patterns in various visual processing paradigms. It was postulated that feature movement during processing was a primary source of errors. The model was motivated by the failure of existing constructs to provide a natural account of the effects of some salient variables, particularly those relating to lateral interference. Two pilot experiments were carried out using an artificial character set, designed so that feature perturbations, if they occurred, would result in particular error patterns. The pilot results provided some evidence for the concept of feature perturbations. Seven experiments are proposed based on the methodology of the pilot experiments. Their purpose is to verify the pilot results, to test for alternative explanations, and, if verified, to examine the functional properties of the perturbation process. The first and main proposed experiment was completed showing good evidence for a perturbation-like process at the feature level. The research also showed evidence for an independent process involving loss of order information concerning the position of whole objects. The initial proposed research will appear in Perception and Psychophysics, summer 1980. Other experiments are underway to examine the functional properties of the perturbation process.